1. Field of the Invention
The present invention relates to a wireless television system comprising a transmitting device and a wireless television receiver. The transmitting device receives a television broadcast and transmits the television broadcast by wireless transmission. The wireless television receiver receives the television broadcast transmitted by wireless transmission.
2. Description of the Related Art
A wireless television system is known in which a television broadcast wave received in a room is transmitted to another room for watching. In the system, a transmitting device receives a television broadcast wave using an antenna installed outdoors and transmits the received television broadcast wave by wireless transmission. The receiver of the system receives transmitted television broadcast wave and reproduces video and sound.
FIGS. 29A to 29B and FIGS. 29C to 29E are schematic diagrams of conventional prior art showing system configurations of this type of wireless television system. The systems shown in FIG. 29A and FIG. 29B are conventional prior art compatible with analog broadcasting. On the other hand, the systems shown in FIG. 29C to FIG. 29E are compatible with digital broadcasting.
In the system shown in FIG. 29A, the transmitting device receives a television signal using an antenna installed outdoors and demodulates the television signal. Then, the transmitting device converts the television signal into an MPEG-TS signal. The transmitting device transmits the MPEG-TS signal by wireless transmission, using the 2.4 GHz band (a frequency band used for wireless local area networks [LAN]). After receiving the MPEG-TS signal, the wireless television receiver performs MPEG decoding on the MPEG-TS signal and reconstructs the television signal. Then, the wireless television receiver reproduces video and sound.
In the system shown in FIG. 29B, the transmitting device receives a television broadcast wave. The transmitting device converts the received television broadcast wave to, for example, the 300 MHz band, which is a low-power-unlicensed band. Then, the transmitting device transmits the television broadcast wave converted to the 300 MHz band by performing a frequency conversion. The wireless television receiver receives and demodulates the transmitted television broadcast wave, and reproduces video and sound.
The system shown in FIG. 29C is the system shown in FIG. 29A made compatible with digital terrestrial broadcasting. The transmitting device receives a digital broadcast wave. The transmitting device performs orthogonal frequency-division multiplexing (OFDM) demodulation and MPEG decoding on the digital broadcast wave and obtains a television signal. Then, the transmitting device converts the obtained television signal into an MPEG-TS signal and transmits the MPEG-TS signal by wireless transmission, using the frequency band used for wireless LAN. After receiving the MPEG-TS signal, the wireless television receiver performs MPEG decoding on the MPEG-TS signal and reconstructs the television signal. Then, the wireless television receiver reproduces video and sound.
In the system shown in FIG. 29D, the transmitting device receives a digital broadcast wave. The transmitting device performs OFDM demodulation on the digital broadcast wave and obtains an MPEG-TS signal. Then, the transmitting device transmits the obtained MPEG-TS signal as is by wireless transmission, using the 2.4 GHz band. After receiving the MPEG-TS signal, the wireless television receiver performs MPEG decoding on the MPEG-TS signal and reconstructs the television signal. Then, the wireless television receiver reproduces video and sound.
In the system shown in FIG. 29E, the transmitting device receives a digital television broadcast wave. The transmitting device converts the received digital television broadcast wave to, for example, the 30 MHz band and transmits the converted television broadcast wave by wireless transmission, using the 30 MHz band. The wireless television receiver receives the transmitted television broadcast wave. The wireless television receiver performs OFDM demodulation and MPEG decoding on the television broadcast wave and reproduces video and sound. The wireless television system using the type of system shown in FIG. 29E is disclosed in, for example, Japanese Laid-Open (Kokai) Patent Publication No. 2005-012583.